Pyrometer lamp



Aug. 14, 1934. E M AT N 1,970,407

PYROMETER LAMP Filed Dec. '3, 1950 [N YEN TUR ESTELL MI MZTEUN,

.575 .242" TUE NE 2.

Patented Aug. 14, 1934 PATENT OFFICE PYROMETER LAMP Estell M. Watson, East Cleveland, Ohio, assignor to General Electric Company, a corporation of New York Application December 3, 1930, Serial No. 499,743

3 Claims.

My invention relates to so-called pyrometer lamps which areelectric lamps calibrated so that the brightness of the light source, ordinarily a glowing filament, is an indication of temperature and the brightness of a glowing object may be compared therewith to measure the temperature of the latter. According to my invention, I provide in combination with the light source, specifically the filament of such a lamp, a marker disposed adjacent to or substantially in the same plane as the filament and preferably in line with that portion of the filament which it is desired particularly to observe. Ordinarily this would be the central portion of the filament inasmuch as this is less subject to cooling by the lead wires and is therefore of greatest brightness. An eyelet is the preferred marker although other forms may be used. The object is to cause the observer to focus his eyes on the filament, and the background which is the glowing object, the temperature of which is to be measured, is out of focus and an average brightness is observed and compared with that of the filament. In the absence of the marker, the observer might well focus on the object rather than the filament.

The single figure of the drawing is a perspective view of the pyrometer lamp of my invention of which a portion of the glass bulb has been broken away to show the interior.

The lamp shown therein comprises the bulb 10 which is coated except for the circular areas 11 and 12 by an opaque material, the stem 13, the eyelet 14 preferably of metal such as nickel, and the relatively short filament 15. The material covering the bulb was applied by dipping said bulb into a material such as Goodrich acid seal rubber paint #1011, and then removingthe paint from areas 11 and-12 after the. paint has been allowed to harden. The location of these cleared areas should be such that a line passing through their centers is perpendicular to the plane of the filament and passes through the center thereof. The filament 15 is preferably of carbon and is connected by Joints of suitable paste to the leading-in wires 16 and 17 which are connected to the shell 18 and the contact plate 19 respectively of the base.

Theeyelet 14 is so located with reference to the filament that the operator who sights through one cleared area and out the other to match the brightness of the filament to the What I claim as new and desire to secure by Letters Patent of the United States is:

1. A pyrometer lamp comprising a bulb opaque except for small clear areas on opposite sides so of said bulb, a filament in said bulb extending across ,a line connecting said clear areas and a marker adjacent said filament and also in said.

line.

2. In a pyrometer lamp, the combination of a bulb having defined thereon an optical line of vision through said bulb, a filament in said bulb extending across said line and a separate marker 7 located substantially in the same plane as said filament and also in said line.

3. In a pyrometer lamp, the combination of a bulb having defined thereon an optical line of vision through said bulb, a filament in said bulb extending across said line and a separate marker consisting of a small eyelet mounted adjacent said filament and also in said line.

ESTELL M. WATSON. 

